a. Field of the Invention
The present invention relates to the field of power generation, and more particularly to generation of power utilizing hydrogen produced in an aluminum-based water-split reaction.
b. Related Art
Currently, the price of conventional fuels such as fossil fuels and coal has been rising. This is the result of increased demand coupled with falling supply. Some scientists have suggested that fossil fuel reserves are being depleted, which as relates to petroleum they have termed “peak oil”. The possible depletion of conventional fuels has encouraged the search for alternative source of fuels.
Hydrogen is an energy dense chemical that is being investigated for the use as an alternative to the conventional fuels for power generation. Hydrogen burns cleanly and can be regenerated, unlike fossil fuels.
There are many processes that generate hydrogen in the gaseous form, but the problem lies in distributing and storing gaseous hydrogen. Uncompressed gaseous hydrogen requires excessive volume, while compressed hydrogen requires bulky and expensive tanks, hence most transportation vehicles and other mobile devices are not suited to use of stored, gaseous hydrogen.
Instead of being stored in gaseous form, hydrogen can also be produced onsite, or onboard a device or vehicle, for example by hydrolysis or by chemical reaction. For example, metallic aluminum can be oxidized in water to produce hydrogen and also heat. The aluminum is converted by the reaction into an aluminum oxide (referred to as alumina), which is non toxic and the main component of clay and bauxite. The fact that hydrogen can be generated from aluminum “on demand” removes the need of gas storage tanks required for storing hydrogen gas.
Metallic aluminum is inexpensive and is produced from aluminum oxide by a process that uses electricity. The electricity can be generated in a renewable manner, for example by hydroelectric power, making the production of hydrogen from aluminum a green process. In addition, the alumina that is generated from the oxidation of aluminum can be recycled into aluminum.
However, aluminum does not readily react in water. A coating of aluminum oxide quickly forms on aluminum that prevents water from reacting with it. This coat of aluminum oxide is called the passivation layer because it prevents the continued reaction of aluminum with an oxidizer. The passivation layer can be chemically removed. The simplest way of removing the passivation layer is to use a 40% caustic soda solution. Aluminum oxide is a type of glass and glass is readily dissolved in caustic soda. Although caustic soda is very cheap, the reaction is difficult to control, to the point of being potentially dangerous, and caustic soda is not environmentally friendly.
Another process uses large quantities of Gallium as a passivation removal agent. However Gallium is very expensive and the aluminum must be melted with Gallium for the removal of the passivation layer, so that the process suffers significant economic and practical drawbacks. But a positive side of this reaction is that the gallium can be recovered.
An invention makes it possible to introduce hydrogen on the market in an economical and practical fashion, without changing the distribution system or requiring a total overhaul of transportation vehicles and other mobile devices, has the potential to be a “disruptive technology.” A disruptive technology causes a technological paradigm shift with immense beneficial effects to society. The AC electrical power system, for example, is considered a disruptive technology that initiated the post industrial revolution, or the atomic age.
Accordingly, there exists a need for a practical method for producing power that uses hydrogen generated onsite or onboard a device or vehicle rather than relying on stored gaseous hydrogen. Furthermore, there exists a need for such a method that employs a reaction that is controllable and safe, and that is also environmentally benign. Still further, there exists a need for such a method that can be implemented on an inexpensive and economically viable basis.